Since the lithium-ion battery has a higher energy density, it has been widely applied in consumer electronics, electric vehicles and energy storage power stations. Conventional lithium-ion battery uses a liquid electrolyte, a higher lithium ionic conductivity of the liquid electrolyte facilitates lithium ions to transmit between a positive electrode plate and a negative electrode plate. However, a non-aqueous organic solvent in the liquid electrolyte is easily volatilized and flamed, which has been a key factor that affects the safety performance of the lithium-ion battery.
In order to resolve the safety problems of the lithium-ion battery, a series of solid electrolytes are developed. These solid electrolytes comprise polymer solid electrolytes and inorganic solid electrolytes. The polymer solid electrolyte has excellent mechanical processability, however, compared with the liquid electrolyte, the lower electrical conductivity of the polymer solid electrolyte at room temperature (<10−4 S/cm) makes them greatly restricted in applications of the lithium-ion battery. The recent research discoveries a new sulphur-containing inorganic solid electrolyte, the electrical conductivity of which may even be bigger than the electrical conductivity of the conventional liquid electrolyte, however, because the sulphur-containing inorganic solid electrolyte has a weaker mechanical processing property, it is difficult to be fabricated into a solid electrolyte membrane which can be applied in the lithium-ion battery, and the fragility of the sulphur-containing inorganic solid electrolyte also restricts its applications in the consumer electronics.
United States patent document published as No. US20110081580A1 on Apr. 7, 2011 discloses a method of sintering inorganic solid electrolyte particles under a higher temperature to obtain an inorganic solid electrolyte membrane. However, it is very difficult to obtain an inorganic solid electrolyte membrane with a very small thickness (<0.1 mm) by using this method, therefore it is difficult to be applied in higher energy density lithium-ion battery. Moreover, although the inorganic solid electrolyte membrane prepared with this method has an excellent ability of transmitting lithium ions, due to the fragility of the inorganic solid electrolyte itself, the obtained inorganic solid electrolyte membrane will have a weaker mechanical strength, which is easily fractured to lose the ability of transmitting lithium ions when deformation on the inorganic solid electrolyte membrane occurs.
United States patent document with an issuance publication No. U.S. Pat. No. 5,238,759 issued on Aug. 24, 1993 discloses a method of adding Teflon as an adhesive into an inorganic solid electrolyte, then rolling or extruding the inorganic solid electrolyte to obtain an inorganic solid electrolyte membrane. The inorganic solid electrolyte membrane prepared with this method has an excellent mechanical processing property, however, since Teflon has an isolability for lithium ions and the inorganic solid electrolyte particles in the inorganic solid electrolyte membrane prepared with this method cannot contact well with each other, the lithium ionic conductivity of the obtained inorganic solid electrolyte membrane is relatively small, and the rate performance of the assembled lithium-ion battery is also worse.